Pendulum operated inertia switch for safety belt mechanism with reciprocating cam follower

ABSTRACT

The inertia switch includes a vertical tubular member terminating at its bottom in an apertured spherical seat which swingably engages the spherical underface of a head formed at the top of a depending pendulum. The top of the head defines a flat faced cam which confronts the flat underface of a follower slideable in the tubular member and a resilient switch arm extends across the path of the follower to be actuated by the swinging of the pendulum.

- United States Patent 1191 Takada 1 June 4, 1974 [541 PENDULUM OPERATEDINERHA SWITCH 2,176,770 10/1939 Maught ZOO/61.5 I T HANISM MT 2,313,5493/1943 Hornain.. ZOO/61.48

FOR SAFETY BEL MEC 3,175,059 3/1965 Chesnut 200/6152 RECIPROCATING CAMFOLLOWER Takezo Takada, Hikone, Japan Takata Kojyo Co., Ltd., Tokyo,Japan Filed: A r. 9, 1973 App1.,No.: 349,609

Related US. Application Data Division of Ser. No. 161.682, July 12,1971, Pat. No 3,740,000.

Inventor:

Assignee:

U. S. Cl. 200/6148, ZOO/61.52 Int. Cl. 1101b 35/15 Field of Search200/6144, 61.48, 61.46,

References Cited UNITED STATES PATENTS 8/1935 Rode] ZOO/61.48

Primary ExaminerJames R. Scott Attorney, Agent, or FirmW01der & Gross1571 ABSTRACT confronts the flat underface of a follower slideable inthe tubular member and a resilient switch arm extends across the path ofthe follower to beactuated by the swinging of the pendulum.

9 Claims, 7 Drawing Figures PENDULUM OPERATED INERTIA SWITCH F0,

SAFETY BELT MECHANISM WITH RECIPROCATING CAM FOLLOWEIR REFERENCE TORELATED APPLICATION The present application is a Divisional Applicationof co-pending US. Pat. application Ser. No. I6 I ,682 filed July 12,1971 now US. Pat. No. 3,740,000.

BACKGROUND OF THE INVENTION The present invention relates generally toimprovements in vehicle safety or seat belt mechanisms and it relatesparticularly to an improved automatic locking vehicle safety beltrewinding reel.

The conventional vehicle safety belt includes a suitably anchored reelabout which the belt is wound and which is biased by a rewind spring toa belt retracted condition. In normal use the belt is withdrawn from thereel for its full length and the free end of the belt is coupled by atongue and buckle arrangement to the opposite side of the seat to securethe occupant in a restrained condition to the seat. Thebelt is ofadjustable length to accommodate occupants of different girths or sizes.The aforesaid conventional safety belt mechanism possesses numerousdrawbacks. Among these is the requirement of manually adjusting thelength of the seat belt to the size of the respective seat occupant.Another important disadvantage of the conventional seat belt mechanismis that it greatly restricts the movements of the restrained seatoccupant during normal operation of the vehicle, thereby interferringwith the optimum and efficient control of the vehicle by the drivercausing a high degree of discomfort.

SUMMARY or THE INVENTION It is a principal object of the presentinvention to provide an improved vehicle safety belt mechanism.

Another object of the present invention is to provide an improved safetybelt rewinding reel.

Still another object of the present invention is to provide an improvedsafety belt rewinding reel which permits the free movement of the seatoccupant under normal driving conditions, but automatically locks thebelt against withdrawal to tightly restrain the occupant in the seat inthe event that collision or accident conditions occur, such as a rapidacceleration or deceleration, or an excessive inclination or attitude ofthe vehicle which results from accidents such as roll over, upending orthe like.

A further object of the present invention is to provide a device of theabove nature characterized by its reliability, ruggedness, compactness,versatility, adaptability, ease of use and application and the obviationof the need for adjustment to different occupant sizes.

The above and other objects of the present invention will becomeapparent from a reading of the following description taken inconjunction with the accompanying drawings which illustrate a preferredembodiment thereof.

In a sense the present invention contemplates the provision of anautomatic locking safety belt retraction reel mechanism comprising abracket, a reel rotatably mounted on the bracket, a rewind springconnected to the reel and urging the reel to rotate in a belt retractingfirst direction and means for releasably locking the reel againstrotation in a belt withdrawal second direction In the preferred form ofthe improved mechanism the bracket includes a base plate'and upstandingside plates between which the reel is joumalled, ratchets being affixedto opposite ends of the reel proximate the side plate inner faces. Aspiral rewind spring has an inner end secured to the reel shaft and anouter end secured to a housing mounted on a bracket side plate. Atransverse shaft is rockably supported between the bracket side platesand has radially projecting pawlsmovable with the rocking of the shaftinto and out of engagement with the ratchets and a radially projectingcrank arm. A solenoid is mounted on the bracket base plate and actuatesan axially movable armature which is connected by a lost motion linkageto the crank arm so that energization of the solenoid actuates the pawlsand a spring normally retracts the pawls. The solenoid is connected to abattery through an attitude sensing inertia switch.

The improved automatic locking reel obviates any need for adjusting thesafety belt and permits the free movement of the seat occupant. In theevent of a collision or accident resulting in a rapid acceleration ordeceleration or an inclination of the vehicle beyond a predeterminedangle, the reel locks the belt against any withdrawal to safely restrainthe seat occupant. The mechanism is reliable, compact and rugged and ofgreat adaptability and versatility.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view,partially broken away, of a reel mechanism embodying the presentinvention illustrated with the associated inertia switch shown in itsnormal open position;

FIG. 2 is a top. plan view thereof, partially broken DESCRIPTION OF THEPREFERRED EMBODIMENT Referring now to the drawings which illustrate apreferred embodiment of the present invention, the reference numeral 10generally designates the improved automatic locking reel mechanism andII the inertia and tilt actuated switch which controls the locking ofreel mechanism It). Reel mechanism 10 comprises a U shaped mountingbracket 12 including a flat horizontal baseplate I3 and verticalparallel side plates I4 which project from the side edges of base plate13 and terminate at their tops in outwardly directed ears 16 providedwith fastening opening 17. Axially aligned medial 3 openings l8'areformed in the upper part of side plates 14.

i A reel 19 extends between and is rotatably supported by side plates 14and includes a shaft 20 which is journalled at opposite ends bycorresponding bushings 21 in disc plate openings 18. Affixed to shaft 20proximate the inner faces of side walls 14 and spaced therefrom bywashers 22 are similar circular ratchets 23 which define the outerflanges of reel 19, the ratchets 23 having peripherally spaces teeth 24provided with substantially radial shoulders 26 facing in the directionof rotation of reel 19 attendent to the withdrawal of the safety belt. Acoaxial hub member 27 surrounds shaft and extends between and is securedto end flanges 27 and is provided with a longitudinal slot 28. A safetybelt of known construction is wound on hub 27 and has an inner endextending through slot 28 and suitably attached to shaft 20.

An end 29 of shaft 20 projects beyond a side plate 14 and is providedwith a diametric slot 30. A biased spiral wind-up spring 32 surroundsshaft end 29 and has an inner end engaged by and rotatable with slot 30.A cup shaped housing 33 encloses the spring 32 and is positioned on andsuitably affixed to the outer face of said wall 14 and the outer end ofspring 32 is connected to housing 33 so that rotation of reel 19 uponwithdrawal of belt B winds up spring 32. The opposite end of shaft 20has an integrally formed pinion 34 which meshes with a gear, not shown,located in a side wall mounted housing 36, to actuate a suitably bracketmounted switch 37 in response to the withdrawal of a predeterminedlength of belt from the reel. I

A shaft 38 parallel to shaft 20 is rockably' supported by and betweenside plates 14 proximate the lower front periphery of reel 19. A pair oflongitudinally spaced parallel pawl member defining arms 39 havingoblique end faces project radially from shaft 38 and are swingable intoand out of engagement with ratchets 23 with the rocking of shaft 38. A'crank arm 40 projects radially upwardly from shaft 38 intermediate theends thereof.

An encased longitudinally extending solenoid 41 is mounted atop bracketbase plate 13 below reel 19 and I is suitably secured to base plate 13by way of flanges projecting from the bottom of the solenoid housing.Solenoid 41 is provided with an axial bore which is longitudinallyslideably engaged by a plunger type cylindrical armature 42 formed of amagnetic material. An angular link member 43 provides a lost motionconnection between armature 42 and crank arm 40. Link member 43 includesa horizontal longitudinal bottom leg 44 engaging an end slot in armature42 and secured thereto by a pin 46 engaged by aligned bores in armature42 and leg 44 and projecting above and below armature 42, a forwardlyupwardly inclined intermediate leg 47 and a forwardly projectinghorizontal top leg 48 of greater width than bottom leg 44. Top leg 48slideably rests on shaft 38 and has a rectangular opening 49 formedtherein which engages crank arm 40. The thickness of crank arm 40 issomewhat less than the corresponding dimension of opening 49 to providea longitudinal lost motion connection between crank arm 40 and linkmember 43. A helical spring 50 encircles the outer end of armature 42and is entrapped between pin 46 and the front face of the solenoidcasing to normally urge armature 42 to its outwardly advanced position,as shown in FIGS. 4 and 8, in which position link member 43 rocks crankarm 40 and shaft 38 to positions which swing pawls 39 to their unlockpositions out of engagement with ratchets 23. Upon energization ofsolenoid 41, armature 42 is retracted into solenoid 41 against theinfluence of spring 50 to swing pawls 39 by way of link 43 crank arm 40and shaft 38 to their reel lock positions in engagement with ratchets 23as shown in F K].

The bracket 12 with the various components mounted thereon nests and ishoused in a casing 51. Casing 51 comprises a receptacle portion 52 and acover member 53, the receptacle portion 52 including a rectangularbottom wall, and upstanding rectangular front and rear walls 54 and 56respectively and side walls 57. Front and rear walls 54 and 56 areprovided with upwardly directed lips 58 outwardly offset from the topedges thereof and the side walls 57 are provided at their tops withoutwardly projecting, medially apertured ears 59 corresponding in shapeto bracket ears 16 and terminating in upwardly directed lips 60. Bracketears 16 rest on casing ears 59 with their respective medial apertures inaxial alignment and bracket base 13 overlies casing bottom wall andsubstantially coincides therewith.

The cover member 53 is in the form of an inverted dish shaped cap havinga flat top wall 63 joined to a downwardly outwardly inclined curvedperipheral wall 64 terminating in a depending lip 65 which tightlyengages and mates the outer face of the receptacle lips 58 and 60. Inorder to provide a passageway for belt B from reel 19 a transverse slot66 of a width greater than that of belt B is formed in the cover forwardwall and the forward border of slot 66 is inwardly downwardly curved, asat 67 and the rear border thereof is upwardly forwardly covered. Thebracket member 12 with its mounted components and the casing 51 arelocked in their assembled condition and desirably mounted by suitablefasteners by way of the apertures formed in cars 16 and 59 and in covermember 53, the cover member 53 being provided with depending ribsbearing on the topfaces of bracket ears 16.

The inclination and acceleration responsive switch 11 comprises ahousing 68 which is closed by a top lid member 69 provided with anintegrally formed centrally positioned upwardly directed open endedcylinder 70. A seat defining inwardly directed peripheral lip 71 isformed about the bottom edge of cylinder 70, the upper face of lip 71being a spherical surface. A pendulum member 76 includes a vertical rod72 supporting at its bottom end a heavy weight 73 and terminating at itstop in a head 74 with spherical bottom face resting on seat 71 and aflat top face, head 74 and seat 71 de fining a ball and socket jointpermitting the free swinging of pendulum 76 in any direction. A flatbottomed follower member defining piston member 76a formed of a plasticor other insulative material slideably engages a cylinder for freevertical sliding therein and is provided with a centrally locatedupwardly directed boss 77.

A pair of mutually insulated switch contact members 78 and 79 aremounted in cover plate 69 are in normally open position. Contact member78 includes a vertical leg 80 provided with a coupling lug 83 at itsbottom secured to cover plate 69 and insulated therefrom and terminatingat its top in a horizontal leg 81. Contact member 79 includes a verticalleg 82 provided at its bottom with a coupling lug likewise secured to tcover plate 69 andinsulated therefrom. A horizontal resilient switcharm' 84 extends from the upper end of leg 82 diametrically over the topof cylinder 70 to a position directly beneath contact leg 81. Adepending first dimple 86 is formed in switch arm 84 in verticalalignment and normally a short distance above boss 77 and a secondupwardly directed dimple 87 is formed on the free end of switch arm 84in vertical alignment with and normally below switch contact leg 81.When pendulum member 76a is swung a predetermined angle from itsvertical due to a rapid acceleration or deceleration of switch 11, asshown in FIG. 5, or when the casing 68 is tilted relative to pendulum76, hemispherical member 74 swings in socket 71 so that its top flat camsurface, as seen in FIG. 5, bears on and raises piston 76a with boss 77bearing on dimple 86 to raise switch arm 84 into closed contact withcontact leg 81 and thereby close normally open switch 11.

One terminal of solenoid 41 is connected either directly or through amanually controlled switch to one terminal of a battery 88, the otherterminal of battery 88 being connected to switch lug 75. The otherterminal of solenoid 41 is connected to switch lug 83.

In the application and operation of the improved safety belt mechanismthe encased reel mechanism is suitably mounted to the vehicle in theknown manner in association with a vehicle seat so that the belt B, incooperation with a suitably positioned and anchored buckling device maybe employed as a shoulder belt. The seat occupant withdraws the belt Bfrom reel 19 through opening 66 passes it across his torso and couplesthe free end thereof to an opposing anchored coupling member. Suchwithdrawal of the belt permitted by reason of pawls 39 being springurged out of engagement with ratchets 23 and the beltwithdrawal windsspring 32 so that belt B is urged toward its retracted position. Thebelt engaged occupant is free to move since,

as aforesaid, the belt is free to be withdrawn and is only spring urgedto a retracted condition.

However, in the event of a rapid acceleration or deceleration of thevehicle or an excessive inclination thereof which characterizes or isthe result of an accident or collision, the change in the relativeposition between pendulum 76 and switch casing 68 closes switch 11, asexplained above, to connect battery 86 across solenoid 41 and energizesolenoid 41 to thereby retract armature 42. The armature 42 by way oflink 43 rocks shaft 38 to swing'pawls 39 into locking engagement withratchets 23 and prevent the rotation of reel 19 and any withdrawl ofbelt B. The occupant is thus restricted from forward motion and safelyrestrained to his seat to minimize or prevent injury to the occupant.Upon the vehicle returningto' normal, switch 11 opens to deenergizesolenoid 41 and permit the spring return of pawls 39 to their ratchetdisengagepositions.

While there has been described and illustrated a preferred embodiment ofthe present invention, it is apparent that numerous alterations,omissions and additions may be made without departing from the spiritthereof.

What is claimed is: ll. An inertia switch device comprising a supportingmember, a vertically extending tubular socket member located on saidsupporting member, a switch including a contact element and a switch armmounted on said support member and being mutually electricallyinsulated, said switch arm extending across the top of said socketmember and being movable between an actuated and a deactuated positionto alternatively engage and disengage said contact element and normallyurged to its deactuated position, a pendulum depending from saidsupporting member for universal swinging relative to said supportingmember and including a head member located at the upper part of saidpendulum and being angularly movable with the swinging of said pendulumand having a cam defining upper face registering with the lower part ofsaid tubular socket member, and means including a follower memberengaging said cam and vertically slidably movable in said tubular socketmember by said cam to an advanced raised position to move said arm toits actuated position when said pendulum swings a predetermined anglefrom its normal rest position and is slidably movable to a lowerretracted position to permit the movement of said switch arm to itsdeactuated position when the angle of said pendulum relative to saidrest position is less than said predetermined angle.

2. The device of claim 1 wherein said follower member is formed of anelectrical insulative material and when in its advanced position engagesand raises said switch arm.

3. The device of claim 2 wherein said switch arm engages said contactelement when said switch is actuated. I

4. The device of claim 2 wherein said pendulum includes a pendulum armand a weight at the lower end of said pendulum arm, said head memberbeing located at the upper end of said'pendulum arm and having a,

sphericallysurfaced underface and said tubular socket member having atits lower part a spherically surfaced socket face engaging said headunderface to define therewith a ball and socket joint.

5. The device of claim 4said follower member slidably registering withsaid tubular socket member for axial movement therein and said switcharm being disposed in the path of said follower member.

6. The device of claim 5 wherein the underface of said follower memberis flat and the cam defining face of said head is flat and coincideswith said follower member underface when said pendulum is in its normalrest position.

7. The device of claim 5 wherein aid follower member includes aprojection centrally located on its top face and said switch armincludes a depending dimple in vertical alignment with said boss.

8. The device of claim 5 wherein said socket member is provided with aninwardly directed lip along its upper edge.

9. The device of claim 5 said supporting member comprising a mountingplate, said socket member being integrally formed with said mountingplate and said switch arm and contact element being positioned on saidmounting plate.

1. An inertia switch device comprising a supporting member, a verticallyextending tubular socket member located on said supporting member, aswitch including a contact element and a switch arm mounted on saidsupport member and being mutually electrically insulated, said switcharm extending across the top of said socket member and being movablebetween an actuated and a deactuated position to alternatively engageand disengage said contact element and normally urged to its deactuatedposition, a pendulum depending from said supporting member for universalswinging relative to said supporting member and including a head memberlocated at the upper part of said pendulum and being angularly movablewith the swinging of said pendulum and having a cam defining upper faceregistering with the lower part of said tubular socket member, and meansincluding a follower member engaging said cam and vertically slidablymovable in said tubular socket member by said cam to an advanced raisedposition to move said arm to its actuated position when said pendulumswings a predetermined angle from its normal rest position and isslidably movable to a lower retracted position to permit the movement ofsaid switch arm to its deactuated position when the angle of saidpendulum relative to said rest position is less than said predeterminedangle.
 2. The device of claim 1 wherein said follower member is formedof an electrical insulative material and when in its advanced positionengages and raises said switch arm.
 3. The device of claim 2 whereinsaid switch arm engages said contact element when said switch isactuated.
 4. The device of claim 2 wherein said pendulum includes apendulum arm and a weight at the lower end of said pendulum arm, saidhead member being located at the upper end of said pendulum arm andhaving a spherically surfaced underface and said tubular socket memberhaving at its lower part a spherically surfaced socket face engagingsaid head underface to define therewith a ball and socket joint.
 5. Thedevice of claim 4 said follower member slidably registering with saidtubular socket member for axial movement therein and said switch armbeing disposed in the path of said follower member.
 6. The device ofclaim 5 wherein the underface of said follower member is flat and thecam defining face of said head is flat and coincides with said followermember underface when said pendulum is in its normal rest position. 7.The device of claim 5 wherein aid follower member includes a projectioncentrally located on its top face and said switch arm includes adepending dimple in vertical alignment with said boss.
 8. The device ofclaim 5 wherein said socket member is provided with an inwardly directedlip along its upper edge.
 9. The device of claim 5 said supportingmember comprising a mounting plate, said socket member being integrallyformed with said mounting plate and said switch arm and contact elementbeing positioned on said mounting plate.